Tocolytics

Maternity & Reproductive

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Examples

terbutalinenifedipineindomethacinmagnesium sulfate

Prefix / Suffix: No consistent suffix

Physiology

Preterm contractions can shorten the cervix and lead to early birth. Tocolytics relax uterine smooth muscle to delay delivery long enough for steroids, transfer, or fetal benefit.

Mechanism of Action

They reduce uterine contractility through beta-2 stimulation, calcium-channel blockade, prostaglandin inhibition, or decreased neuromuscular excitability depending on the medication.

Indications

Short-term delay of preterm labor
Allow time for antenatal corticosteroids
Allow maternal transfer to higher level care
Temporary management of uterine tachysystole in selected cases

Side Effects / Adverse Effects

Maternal tachycardia and palpitations with terbutaline
Hypotension and headache with nifedipine
Oligohydramnios or premature ductus arteriosus closure with indomethacin
Respiratory depression and loss of reflexes with magnesium toxicity

Contraindications

Intrauterine infection
Significant maternal bleeding or instability
Severe preeclampsia/eclampsia requiring delivery
Nonreassuring fetal status
Gestational age or fetal condition where delivery is safer

Nursing Considerations

Monitor maternal vital signs and fetal heart rate
Assess contraction pattern and cervical change
For magnesium: monitor respirations, deep tendon reflexes, urine output, and have calcium gluconate available
Teach that tocolytics usually delay labor temporarily, not stop it permanently
Report chest pain, dyspnea, severe hypotension, or decreased fetal movement

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Disclaimer: PharmPal Nurse is for education only and is not medical advice. Do not use it to diagnose, treat, prescribe, or make patient-care decisions; always verify with current drug references, your instructor, facility policy, and a licensed provider. In emergencies, call local emergency services.